JP2013210498A - Photosensitive conductive paste and conductive circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide photosensitive conductive paste capable of forming a conductive circuit which has low resistance and high resolution.SOLUTION: Photosensitive conductive paste comprises: organic binder; conductive powder; a photopolymerizable monomer; an oxime ester based photopolymerization initiator; and at least one kind of thiodiglycolic acid, and a thiodiglycolic acid derivative.

Description

  The present invention relates to a photosensitive conductive paste for forming a conductive circuit on a substrate and a conductive circuit using the same.

  In recent years, a highly integrated LSI and a multilayer circuit board for mounting a large number of various electronic components, or a flat panel display (hereinafter also referred to as “FPD”) such as a plasma display panel (hereinafter also referred to as “PDP”). However, there is an increasing demand for downsizing, high density, high definition, etc., and finer circuit and electrodes formed on these are increasingly required.

  As a method of forming a conductive circuit, a circuit forming method using a printing technique such as screen printing using a non-photosensitive conductive paste in which conductive powder is mixed in an organic binder is widely known (for example, Patent Document 1) reference). However, in screen printing, it is difficult to form a conductor pattern having a line width of 100 μm or less in an industrially stable manner, and there are limits to the fine patterns that can be created. Further, since the dimensional error of the mask pattern increases as the printing mask becomes larger, for example, in the case of a PDP of 30 inches or more, production of a high-definition PDP is technically difficult.

  On the other hand, as a method of forming a conductive circuit having a line width of 100 μm or less, a method of forming a conductive circuit on a substrate using a photosensitive conductive paste and utilizing a photolithography technique is known ( For example, see Patent Document 2). According to this method, a high-definition conductive circuit can be formed as compared with the case where screen printing is used.

  On the other hand, to reduce the resistance of the conductive circuit, it is necessary to increase the content ratio of the conductive powder in the paste. However, in the technique using the photolithography technique, it is difficult to sufficiently cure the inside (deep part) of the coating film by the conductive powder, and it is necessary to irradiate irradiation light for a long time, and thus the radical generated by the reaction. In addition, there is a problem that the diffusion of the active species proceeds and the resolution of the conductive circuit is lowered.

JP-A-10-269848 (claims, etc.) Patent No. 3520798 (claims, etc.)

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a photosensitive conductive paste having high resolution and suitable for forming a low-resistance conductive circuit.

  The photosensitive conductive paste according to this embodiment includes at least one of an organic binder, conductive powder, a photopolymerization monomer, an oxime ester-related photopolymerization initiator, thiodiglycolic acid and a derivative of thiodiglycolic acid. It is characterized by containing 1 type. With such a structure, a high-resolution and low-resistance conductive circuit can be formed. Moreover, it is preferable that the said conductive powder contains silver powder. Further, these photosensitive conductive pastes are used for forming a conductive circuit.

  According to the photosensitive conductive paste of the present invention, a high-resolution and low-resistance conductive circuit can be formed.

The inventors of the present invention, as a result of intensive investigations on the above problems, in a paste used for forming a conductive circuit, an organic binder, a conductive powder, a photopolymerizable monomer, an oxime ester photopolymerization initiator, It has been found that a conductive circuit having high resolution and low resistance can be formed by containing at least one of thiodiglycolic acid and thiodiglycolic acid derivatives.
That is, by incorporating an oxime ester photopolymerization initiator as a photopolymerization initiator in a photosensitive conductive paste used for forming a conductive circuit, high resolution is achieved, and thiodiglycolic acid and thiodiglycol are further added thereto. It has been found that the resistance can be reduced by containing at least one of acid derivatives, and the present invention has been completed.
Hereinafter, the photosensitive conductive paste of this embodiment will be described in detail.

  The organic binder in the photosensitive conductive paste of the present embodiment is used to form a pattern on a coating film by dispersing conductive powder so that it can be applied onto a substrate and developing it by pattern exposure. .

  As the organic binder, a carboxyl group-containing resin, specifically, a carboxyl group-containing photosensitive resin that itself has an ethylenic double bond and a carboxyl group-containing resin that does not have an ethylenically unsaturated double bond. It can be used. Examples of the resin (which may be either an oligomer or a polymer) that can be suitably used include the following.

(1) A carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth) acrylic acid and a compound having an unsaturated double bond such as methyl (meth) acrylate.
(2) A copolymer of an unsaturated carboxylic acid such as (meth) acrylic acid and a compound having an unsaturated double bond such as methyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylic acid chloride, etc. A carboxyl group-containing photosensitive resin obtained by adding an ethylenically unsaturated group as a pendant.
(3) A copolymer of an epoxy group such as glycidyl (meth) acrylate and an unsaturated double bond and a compound having an unsaturated double bond such as methyl (meth) acrylate, (meth) acrylic acid, etc. A carboxyl group-containing photosensitive resin obtained by reacting an unsaturated carboxylic acid of the above and reacting the resulting secondary hydroxyl group with a polybasic acid anhydride such as tetrahydrophthalic anhydride.
(4) To a copolymer of an acid anhydride having an unsaturated double bond such as maleic anhydride and a compound having an unsaturated double bond such as styrene, a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and A carboxyl group-containing photosensitive resin obtained by reacting a compound having a saturated double bond.
(5) A carboxyl group obtained by reacting a polyfunctional epoxy compound with an unsaturated carboxylic acid such as (meth) acrylic acid, and reacting the resulting secondary hydroxyl group with a polybasic acid anhydride such as tetrahydrophthalic anhydride. Contains photosensitive resin.
(6) An epoxy group of a copolymer of an unsaturated double bond such as methyl (meth) acrylate and a glycidyl (meth) acrylate has one carboxyl group in one molecule, and an ethylenically unsaturated bond A carboxyl group-containing photosensitive resin obtained by reacting an organic acid having no carboxylic acid, and reacting the resulting secondary hydroxyl group with a polybasic acid anhydride.
(7) A carboxyl group-containing resin obtained by reacting a polybasic acid anhydride with a hydroxyl group-containing polymer such as polyvinyl alcohol.
(8) A carboxyl group-containing resin obtained by reacting a hydroxyl group-containing polymer such as polyvinyl alcohol with a polybasic acid anhydride such as tetrahydrophthalic anhydride, an epoxy group such as glycidyl (meth) acrylate, and an unsaturated double group. A carboxyl group-containing photosensitive resin obtained by further reacting a compound having a bond.

Of these, the resins (1), (2), (3), and (6) are particularly preferably used. These resins can be used alone or in combination.
In addition, (meth) acrylate in this specification is a term which generically refers to acrylate, methacrylate and a mixture thereof, and the same applies to other similar expressions.

  The amount of such an organic binder is preferably 1 to 50% by mass based on the nonvolatile component (the component that does not volatilize from the paste in the drying step and remains in the film). When the amount is less than 1% by mass, developability is greatly deteriorated due to the lack of these resins in the coating film to be formed, and patterning by development becomes difficult. On the other hand, when it exceeds 50 mass%, the ratio of the conductive powder is insufficient, and the resistance value tends to deteriorate.

  Moreover, as a weight average molecular weight, it is preferable that it is 1,000-100,000. When the weight average molecular weight is less than 1,000, the adhesion of the coating film at the time of development deteriorates. On the other hand, when the weight average molecular weight exceeds 100,000, development failure tends to occur. More preferably, it is 5,000-70,000. The weight average molecular weight is a value in terms of polystyrene measured by gel permeation chromatography (GPC).

  Moreover, it is preferable that the acid value of the organic binder used is 50-250 mgKOH / g. When the acid value is less than 50 mgKOH / g, the solubility in an alkaline aqueous solution is insufficient, and development failure tends to occur. On the other hand, when the acid value exceeds 250 mgKOH / g, the adhesion of the coating film is deteriorated during development or the photocured part (exposure). Part) will be dissolved.

  Further, the double bond equivalent of the carboxyl group-containing photosensitive resin is preferably 350 to 2,000 g / eq. When the double bond equivalent of the carboxyl group-containing photosensitive resin is less than 350 g / eq, the pattern tends to be thick and the line sharpness tends to deteriorate. On the other hand, if it exceeds 2,000 g / eq, the work margin during development is narrow, and a high exposure amount is required during photocuring. More preferably, it is 400-1500 g / eq.

  Examples of the photopolymerizable monomer include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, polyurethane diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, Pentaerythritol tetraacrylate, trimethylolpropane ethylene oxide-modified triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate and the corresponding methacrylates; phthalic acid, adipic acid, maleic acid, itaconic acid, succinic acid, Polybasic acids such as trimellitic acid and terephthalic acid and hydroxy Alkyl (meth) mono acrylate -, di -, tri -, or the like more polyesters.

  These photopolymerizable monomers can be used alone or in combination of two or more. Among these photopolymerizable monomers, polyfunctional monomers having two or more acryloyl groups or methacryloyl groups in one molecule are preferable.

  As a compounding quantity of such a photopolymerizable monomer, 5-200 mass parts is preferable per 100 mass parts of organic binders as solid content conversion.

The conductive powder in the photosensitive conductive paste of the present embodiment imparts conductivity to the formed conductive circuit. Specifically, for example, Ag, Au, Pt, Pd, Ni, Cu, Al, Sn , Pb, Zn, Fe, Ir, Os, Rh, W, Mo, Ru, and the like. These conductive powders may be used in the form of a single body, or may be any of these alloys, or a multilayer body having any of these as a core or a coating layer. Further, oxides such as tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), and ITO (Indium Tin Oxide) may be used. Among these conductive powders, Ag is preferably used.

  The shape of the conductive powder is not particularly limited, and may be various shapes such as a dentlite shape as well as a spherical shape and a flake shape.

Although there is no restriction | limiting in particular as a particle size of electroconductive powder, For example, when using spherical electroconductive powder, an average particle diameter is 0.1-5 micrometers, Preferably it is 0.2-3 micrometers. Moreover, when using flaky conductive powder, an average particle diameter is 0.1-5 micrometers, Preferably it is 0.3-3 micrometers.
In addition, an average particle diameter is calculated | required by calculating the average which measured 10 random electroconductive powders observed using SEM (scanning electron microscope).
The flaky silver powder specifically refers to silver powder having an aspect ratio of 3 or more. The aspect ratio can be obtained by (average particle diameter / average thickness T).
Here, “average particle diameter” indicates an average long diameter L of 10 particles measured in the longitudinal direction with a scanning electron microscope, and “average thickness T” indicates particles measured in the thickness direction with a scanning electron microscope. Ten average thicknesses T are shown.

  Such conductive powder is preferably 30 to 90% by mass based on the nonvolatile component of the photosensitive conductive paste (the component that does not volatilize from the paste in the drying step and remains in the film). If it is less than 30% by mass, it will be difficult to obtain sufficient electrical conductivity. If it exceeds 90% by mass, the light at the time of exposure will not penetrate to the deep part of the coating film, so that the photocurability of the deep part will deteriorate, and the fine line pattern Cannot be formed. More preferably, it is 50-85 mass%.

Thiodiglycolic acid is conventionally added to impart stability of the metal plating solution, but in this embodiment, as described above, the oxime ester-based photopolymerization described later as the photosensitive conductive paste used for forming the conductive circuit as described above. By using it together with an initiator, it is possible to achieve high resolution and low resistance conductive circuit formation.
A thiodiglycolic acid such as deer grade 1 manufactured by Kanto Chemical Co., Inc. can be used.
In addition, formation of a low-resistance conductive circuit can be achieved using a thiodiglycolic acid derivative.
Examples of thiodiglycolic acid derivatives include 3,3′-thiodipropionic acid, diallyl thiodiacetic acid, thiobis (butyl acetate), disodium thiodiglycolate, bis (2,2′-thiodiacetic acid bis (2- Ethylhexyl), dioctyl thiodiacetate, 2,2′-thiobis (methyl acetate), dipotassium thiodiglycolate and the like.

  The blending ratio of at least one of thiodiglycolic acid and thiodiglycolic acid derivatives is preferably 0.01 to 10 parts by mass per 100 parts by mass of the organic binder in terms of solid content. If it is less than 0.01 parts by mass, the conductivity is deteriorated, which is not preferable. On the other hand, when the amount exceeds 10 parts by mass, the conductivity deteriorates in the same manner, and the patterning property is improved by at least one of the properties of thiodiglycolic acid and thiodiglycolic acid derivatives having very good developability. Is not preferable because it deteriorates. More preferably, it is 0.1-5 mass parts.

（式中、Ｒ^１は、水素原子、フェニル基（炭素数１〜６のアルキル基、フェニル基、もしくはハロゲン原子で置換されていてもよい）、炭素数１〜２０のアルキル基（１個以上の水酸基で置換されていてもよく、アルキル鎖の中間に１個以上の酸素原子を有していてもよい）、炭素数５〜８のシクロアルキル基、炭素数２〜２０のアルカノイル基またはベンゾイル基（炭素数が１〜６のアルキル基もしくはフェニル基で置換されていてもよい）を表し、Ｒ^２は、フェニル基（炭素数１〜６のアルキル基、フェニル基もしくはハロゲン原子で置換されていてもよい）、炭素数１〜２０のアルキル基（１個以上の水酸基で置換されていてもよく、アルキル鎖の中間に１個以上の酸素原子を有していてもよい）、炭素数５〜８のシクロアルキル基、炭素数２〜２０のアルカノイル基またはベンゾイル基（炭素数が１〜６のアルキル基もしくはフェニル基で置換されていてもよい）を表す。）
下記一般式（II）で示される２−（アセチルオキシイミノメチル）チオキサンテン−９−オン、

下記一般式（III）で表される化合物、

（式中、Ｒ^３およびＲ^４は、それぞれ独立に、炭素数１〜１２のアルキル基を表し、Ｍは、Ｓ、ＯまたはＮＨを表し、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８およびＲ^９は、それぞれ独立に、水素原子または炭素数１〜６のアルキル基を表し、ｍおよびｎは、０〜５の整数を表す。）
下記一般式（IV）で表される化合物、

（式中、Ｒ^１０は、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、シクロペンチル基、シクロヘキシル基、フェニル基、ベンジル基、ベンゾイル基、炭素数２〜１２のアルカノイル基、炭素数２〜１２のアルコキシカルボニル基（アルコキシル基を構成するアルキル基の炭素数が２以上の場合、アルキル基は１個以上の水酸基で置換されていてもよく、アルキル鎖の中間に１個以上の酸素原子を有していてもよい）、またはフェノキシカルボニル基を表し、Ｒ^１１、Ｒ^１３は、それぞれ独立に、フェニル基（炭素数１〜６のアルキル基、フェニル基もしくはハロゲン原子で置換されていてもよい）、炭素数１〜２０のアルキル基（１個以上の水酸基で置換されていてもよく、アルキル鎖の中間に１個以上の酸素原子を有していてもよい）、炭素数５〜８のシクロアルキル基、炭素数２〜２０のアルカノイル基またはベンゾイル基（炭素数が１〜６のアルキル基もしくはフェニル基で置換されていてもよい）を表し、Ｒ^１２は、水素原子、フェニル基（炭素数１〜６のアルキル基、フェニル基もしくはハロゲン原子で置換されていてもよい）、炭素数１〜２０のアルキル基（１個以上の水酸基で置換されていてもよく、アルキル鎖の中間に１個以上の酸素原子を有していてもよい）、炭素数５〜８のシクロアルキル基、炭素数２〜２０のアルカノイル基またはベンゾイル基（炭素数が１〜６のアルキル基もしくはフェニル基で置換されていてもよい）を表す。）
下記一般式（V）で表される化合物や、

（式中、Ｒ^１４は、炭素数１〜２０のアルキル基、炭素数６〜３０のアリール基、炭素数７〜３０のアリールアルキル基またはＣＮを表し、アルキル基、アリール基およびアリールアルキル基の水素原子は、更にＯＲ^４１、ＣＯＲ^４１、ＳＲ^４１、ＮＲ^４２Ｒ^４３、−ＮＣＯＲ^４２−ＯＣＯＲ^４３、ＣＮ、ハロゲン原子、−ＣＲ^４１＝ＣＲ^４２Ｒ^４３またはＣＯ−ＣＲ^４１＝ＣＲ^４２Ｒ^４３で置換されていてもよく、Ｒ^４１、Ｒ^４２およびＲ^４３は、それぞれ独立に、水素原子、炭素数１〜２０のアルキル基、炭素数６〜３０のアリール基、炭素数７〜３０のアリールアルキル基または炭素数２〜２０の複素環基を表し、Ｒ^１５は、Ｒ^５１またはＯＲ^５１を表し、Ｒ^５１は、炭素数１〜２０のアルキル基、炭素数６〜３０のアリール基または炭素数７〜３０のアリールアルキル基を表し、アルキル基、アリール基およびアリールアルキル基の水素原子は、更にハロゲン原子で置換されていてもよく、Ｒ^１６は、炭素数１〜２０のアルキル基、炭素数６〜３０のアリール基または炭素数７〜３０のアリールアルキル基を表し、Ｒ^１４、Ｒ^１６、Ｒ^４１、Ｒ^４２およびＲ^４３で表される置換基のアルキレン部分のメチレン基は、不飽和結合、エーテル結合、チオエーテル結合、エステル結合、チオエステル結合、アミド結合またはウレタン結合により１〜５回中断されていてもよく、上記置換基のアルキル部分は分岐側鎖があってもよく、環状アルキルであってもよく、上記置換基のアルキル末端は不飽和結合であってもよく、Ｒ^１６は、隣接するベンゼン環と一緒になって環を形成していてもよい。Ｒ^１７およびＲ^１８は、それぞれ独立に、Ｒ^５１、ＯＲ^５１、ＣＮまたはハロゲン原子を表し、ａおよびｂは、それぞれ独立に、０〜３である。）、
下記一般式（VI）で表されるカルバゾール２量体を有する化合物を用いることができる。

（式中、Ｒ^１９は、水素原子、炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、フェニル基、フェニル基（炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、アミノ基、炭素数１〜８のアルキル基を持つアルキルアミノ基またはジアルキルアミノ基により置換されている）、ナフチル基（炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、アミノ基、炭素数１〜８のアルキル基を持つアルキルアミノ基またはジアルキルアミノ基により置換されている）を表し、Ｒ^２０、Ｒ^２１はそれぞれ、水素原子、炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、ハロゲン基、フェニル基、フェニル基（炭素数１〜１７のアルキル基、炭素数１〜８のアルコキシ基、アミノ基、炭素数１〜８のアルキル基を持つアルキルアミノ基またはジアルキルアミノ基により置換されている）、ナフチル基（炭素数1〜17のアルキル基、炭素数1〜8のアルコキシ基、アミノ基、炭素数１〜８のアルキル基を持つアルキルアミノ基またはジアルキルアミノ基により置換されている）、アンスリル基、ピリジル基、ベンゾフリル基、ベンゾチエニル基を表し、Ａｒは、炭素数１〜１０のアルキレン、ビニレン、フェニレン、ビフェニレン、ピリジレン、ナフチレン、アントリレン、チエニレン、フリレン、２，５−ピロール−ジイル、４，４’−スチルベン−ジイル、４，２ ’−スチレン−ジイルを表し、ｎは０または１の整数である。） Oxime ester-based photopolymerization initiators have high photosensitivity, so even a paste containing a large amount of conductive powder can be sufficiently photocured with a small amount of exposure, resulting in a conductive circuit with high resolution. Can be formed.
As such an oxime ester photopolymerization initiator, for example, a compound having a group represented by the following general formula (I),

(In the formula, R ¹ represents a hydrogen atom, a phenyl group (which may be substituted with an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a halogen atom), an alkyl group having 1 to 20 carbon atoms (one or more). Which may have one or more oxygen atoms in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms, or benzoyl Represents a group (which may be substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group), and R ² is a phenyl group (substituted with an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom). Or an alkyl group having 1 to 20 carbon atoms (which may be substituted with one or more hydroxyl groups, and may have one or more oxygen atoms in the middle of the alkyl chain), carbon number 5 ~ 8 cycloalkyl groups It represents an alkanoyl group or benzoyl group having 2 to 20 carbon atoms (carbon atoms may be substituted with 1-6 alkyl or phenyl group).)
2- (acetyloxyiminomethyl) thioxanthen-9-one represented by the following general formula (II):

A compound represented by the following general formula (III):

(Wherein R ³ and R ⁴ each independently represents an alkyl group having 1 to 12 carbon atoms, M represents S, O or NH, and R ⁵ , R ⁶ , R ⁷ , R ⁸ and R ⁹ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and m and n each represents an integer of 0 to 5.)
A compound represented by the following general formula (IV):

(In the formula, R ¹⁰ is a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyclopentyl group, a cyclohexyl group, a phenyl group, a benzyl group, a benzoyl group, an alkanoyl group having 2 to 12 carbon atoms, or 2 carbon atoms. To 12 alkoxycarbonyl groups (when the alkyl group constituting the alkoxyl group has 2 or more carbon atoms, the alkyl group may be substituted with one or more hydroxyl groups, and one or more oxygen atoms in the middle of the alkyl chain) Or R ¹¹ and R ¹³ each independently represents a phenyl group (an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom may be substituted). Good), an alkyl group having 1 to 20 carbon atoms (which may be substituted with one or more hydroxyl groups, and has one or more oxygen atoms in the middle of the alkyl chain). Or a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms or a benzoyl group (which may be substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group), and R ¹² is a hydrogen atom, a phenyl group (which may be substituted with an alkyl group having 1 to 6 carbon atoms, a phenyl group or a halogen atom), an alkyl group having 1 to 20 carbon atoms (which is substituted with one or more hydroxyl groups). And may have one or more oxygen atoms in the middle of the alkyl chain), a cycloalkyl group having 5 to 8 carbon atoms, an alkanoyl group having 2 to 20 carbon atoms or a benzoyl group (having 1 carbon atom). To 6 alkyl groups or phenyl groups).
A compound represented by the following general formula (V),

(In the formula, R ¹⁴ represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, or CN, and includes an alkyl group, an aryl group, and an arylalkyl group. hydrogen atoms, further ^{oR 41, COR 41, SR 41} , NR 42 R 43, -NCOR 42 -OCOR 43, CN, halogen ^atom, -CR 41 ^{= CR} 42 ^{R 43} or ^{CO-CR 41 = CR 42 R} 43 R ⁴¹ , R ⁴² and R ⁴³ each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an arylalkyl having 7 to 30 carbon atoms. a heterocyclic group groups or 2 to 20 carbon ^{atoms, R 15 represents R 51} or ^{oR 51, R 51} is an alkyl group having 1 to 20 carbon atoms, 6 carbon atoms Represents 0 aryl group or an arylalkyl group having 7 to 30 carbon atoms, an alkyl group, a hydrogen atom of the aryl and arylalkyl groups may be further substituted by a halogen atom, R ¹⁶ is 1 to carbon atoms Represents an alkyl group having 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an arylalkyl group having 7 to 30 carbon atoms, and the alkylene group of the substituent represented by R ¹⁴ , R ¹⁶ , R ⁴¹ , R ⁴² and R ⁴³ The methylene group may be interrupted 1 to 5 times by an unsaturated bond, an ether bond, a thioether bond, an ester bond, a thioester bond, an amide bond or a urethane bond, and the alkyl part of the above substituent has a branched side chain. may be, may be a cyclic alkyl, alkyl-terminus of the above substituents may be unsaturated bond, R ¹⁶ is adjacent benzene Ring good ^{.R 17} and also form a ring together with ^{R 18} each ^{independently} represent R ^{51, OR} 51, CN or halogen atom, a and b are each independently 0 3).
A compound having a carbazole dimer represented by the following general formula (VI) can be used.

(In the formula, R ¹⁹ is a hydrogen atom, an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, a phenyl group (an alkyl group having 1 to 17 carbon atoms, an alkyl group having 1 to 8 carbon atoms). An alkoxy group, an amino group, an alkylamino group having an alkyl group having 1 to 8 carbon atoms or a dialkylamino group), a naphthyl group (an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms) R ²⁰ and R ²¹ are each a hydrogen atom, an alkyl group having 1 to 17 carbon atoms, and an amino group, an alkylamino group having an alkyl group having 1 to 8 carbon atoms or a dialkylamino group. C1-C8 alkoxy group, halogen group, phenyl group, phenyl group (C1-C17 alkyl group, C1-C8 alkoxy group, amino group, C1-C8 alkyl group Substituted with an alkylamino group or dialkylamino group having a naphthyl group (having an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amino group, or an alkyl group having 1 to 8 carbon atoms) An anthryl group, a pyridyl group, a benzofuryl group, a benzothienyl group, and Ar represents alkylene having 1 to 10 carbon atoms, vinylene, phenylene, biphenylene, pyridylene, naphthylene, substituted with an alkylamino group or a dialkylamino group) Anthrylene, thienylene, furylene, 2,5-pyrrole-diyl, 4,4′-stilbene-diyl, 4,2′-styrene-diyl, and n is an integer of 0 or 1.

  Examples of commercially available products include CGI-325 manufactured by BASF Japan, IRGACURE (registered trademark) OXE01, IRGACURE OXE02, NCI-831 manufactured by ADEKA, and the like.

  The blending ratio of the oxime ester-based photopolymerization initiator is preferably 0.01 to 30 parts by mass per 100 parts by mass of the organic binder in terms of solid content. If it is less than 0.01 parts by mass, the photocurability becomes insufficient and the pattern tends to be chipped. Further, the surface curability is insufficient, the coating surface is damaged during development, and the resistance value is deteriorated. On the other hand, if it exceeds 30 parts by mass, pattern halation occurs and the sharpness of the pattern edge portion deteriorates. In addition, the penetrability of the pattern deteriorates, and a pattern with a small space cannot be drawn. More preferably, it is 0.05-5 mass parts.

  Moreover, you may use together photoinitiators other than the above-mentioned oxime ester type | system | group. Specific examples of such photopolymerization initiators include benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; acetophenone, 2,2-dimethoxy-2-phenylacetophenone , Acetophenones such as 2,2-diethoxy-2-phenylacetophenone and 1,1-dichloroacetophenone; 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2 -Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4- Aminoacetophenone such as morpholinyl) phenyl] -1-butanone Anthraquinones such as 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone; 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4- Thioxanthones such as diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone; or xanthones; (2,6-dimethoxybenzoyl) -2,4,4-pentylphosphine oxide, bis ( 2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl-2,4,6-trimethylbenzoy Phosphine oxides such as diphenyl phosphinate; various peroxides and the like. As a photopolymerization initiator, Irgacure 389 manufactured by BASF Japan can also be suitably used.

  Examples of commercially available products include IRGACURE 184, IRGACURE 819, IRGACURE 907, IRGACURE 369, IRGACURE 379, and Lucillin (registered trademark) TPO manufactured by BASF Japan. In addition, it is not limited to these, Moreover, these photoinitiators can be used individually or in combination of 2 or more types with an oxime ester system photoinitiator.

  The above-mentioned photopolymerization initiator includes tertiary amines such as N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, and triethanolamine. It can be used in combination with one or more photosensitizers such as

  Moreover, in order to react an uncured photopolymerizable component as needed, a thermal polymerization catalyst can be used in combination with the above-described photopolymerization initiator. The thermal polymerization catalyst can react with an uncured photopolymerizable component by aging at a high temperature of about several minutes to 1 hour.

  Examples of such a thermal polymerization catalyst include peroxides such as benzoyl peroxide and azo compounds such as isobutyronitrile, and preferably 2,2′-azobisisobutyronitrile, 2,2′- Azobis-2-methylbutyronitrile, 2,2′-azobis-2,4-divaleronitrile, 1,1′-azobis-1-cyclohexanecarbonitrile, dimethyl-2,2′-azobisisobutyrate, 4,4′-azobis-4-cyanovaleric acid, 2-methyl-2,2′-azobispropanenitrile, 2,4-dimethyl-2,2,2 ′, 2′-azobispentanenitrile, 1 , 1′-azobis (1-acetoxy-1-phenylethane), 2,2,2 ′, 2′-azobis (2-methylbutanamide oxime) dihydrochloride, and the like.

In the photosensitive conductive paste of this embodiment, an organic solvent can be used in order to adjust the viscosity and form a uniform coating film.
Examples of such organic solvents include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol Glycol ethers such as monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene Glycol monomethyl ether acetate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyle Esters such as ethanol; alcohols such as ethanol, propanol, ethylene glycol, propylene glycol, and terpineol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha These can be used alone or in combination of two or more.

  In such a photosensitive conductive paste, a stabilizer can be added in order to further improve the storage stability and suppress the deterioration of the coating workability due to the gelation or the decrease in fluidity.

  As such a stabilizer, a compound having an effect of complexing with the conductive powder in the photosensitive conductive paste or forming a salt can be used.

  Specifically, for example, various inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, boric acid; formic acid, acetic acid, acetoacetic acid, citric acid, stearic acid, maleic acid, fumaric acid, phthalic acid, benzenesulfonic acid, sulfamic acid, etc. Various organic acids; phosphoric acid, phosphorous acid, hypophosphorous acid, methyl phosphate, ethyl phosphate, butyl phosphate, phenyl phosphate, ethyl phosphite, diphenyl phosphite, mono (2-methacryloyloxyethyl) Examples include acids such as various phosphate compounds (inorganic phosphoric acid, organic phosphoric acid) such as acid phosphate and di (2-methacryloyloxyethyl) acid phosphate. These stabilizers can be used alone or in combination of two or more.

  Furthermore, the photosensitive conductive paste of the present embodiment may be blended with other additives such as a defoaming / leveling agent such as silicone and acrylic, and a silane coupling agent for improving the adhesion of the coating film. it can. Furthermore, a known antioxidant or a thermal polymerization inhibitor for improving the thermal stability during storage may be added.

  The photosensitive electrically conductive paste comprised as mentioned above is prepared by mixing each component, and after stirring with a stirrer etc., it can knead | mix with a 3 roll mill etc. and can be made into a paste.

  The photosensitive conductive paste thus prepared is applied to a substrate such as a glass substrate by an appropriate application method such as a screen printing method, a bar coder, or a blade coater to form a coating film.

  Next, the obtained coating film is dried at, for example, about 70 to 120 ° C. for about 5 to 40 minutes in a hot-air circulating drying furnace, a far-infrared drying furnace or the like in order to obtain a touch-drying property. Dry film). At this time, when a photosensitive conductive paste is previously formed on a film, it may be laminated on a substrate.

Then, selective exposure is performed with respect to the obtained dry coating film. As selective exposure, contact exposure and non-contact exposure using a negative mask having a predetermined exposure pattern are possible. As the exposure light source, for example, a halogen lamp, a high-pressure mercury lamp, a laser beam, a metal halide lamp, a black lamp, an electrodeless lamp, or the like is used. The exposure dose is preferably about 10 to 700 mJ / cm ² .

  Development is performed on the coating film after selective exposure. For the development, a spray method, a dipping method or the like is used. As the developer, it is sufficient that the carboxyl group of the carboxyl group-containing resin contained in the photosensitive conductive paste is saponified and the uncured part (unexposed part) can be removed. For example, sodium hydroxide, potassium hydroxide Metal alkali aqueous solutions such as sodium carbonate, potassium carbonate, and sodium silicate, amine aqueous solutions such as monoethanolamine, diethanolamine, and triethanolamine, particularly dilute alkaline aqueous solutions having a concentration of about 1.5 wt% or less are preferably used. Moreover, it is preferable to perform washing with water and acid neutralization in order to remove an unnecessary developer after development.

  Thereafter, the substrate on which the desired circuit pattern is formed by development is dried or cured at 80 to 300 ° C. for 5 to 60 minutes to form a desired conductive circuit on the base material.

  Hereinafter, although an Example and a comparative example are shown and this embodiment is demonstrated concretely, this invention is not limited to these Examples. In the following, “%” is based on weight unless otherwise specified.

<Synthesis example of organic binder>
A flask equipped with a thermometer, stirrer, dropping funnel, and reflux condenser is charged with methyl methacrylate and methacrylic acid in a molar ratio of 0.87: 0.13, dipropylene glycol monomethyl ether as a solvent, and azobisiso as a catalyst. Butyronitryl was added and stirred at 80 ° C. for 2 to 6 hours under a nitrogen atmosphere to obtain a resin solution containing an organic binder. This organic binder had a weight average molecular weight of about 10,000, an acid value of 74 mgKOH / g, and a solid content of 57%.

  For the measurement of the weight average molecular weight of the obtained organic binder, a high performance liquid chromatograph in which three pumps LC-6AD manufactured by Shimadzu Corporation and three columns Shodex (registered trademark) KF-804, KF-803, and KF-802 manufactured by Showa Denko were connected. The graphic was used.

(Preparation of photosensitive conductive paste)
It mixes with each component and composition ratio shown in Table 1, and after stirring with a stirrer, it pastes by kneading with a 3 roll mill, and each photosensitive conductive paste of Examples 1, 2 and Comparative Examples 1, 2 is used. Prepared. The lightness L * value of the conductive powder used for the photosensitive conductive paste is a value measured according to JIS standard Z8722.

［備考］
＊１：明度L*=７０、平均粒径＝２μｍ
＊２：明度L*= ５８、平均粒径＝１．５μｍ
＊３：オキシムエステル系光重合開始剤；IRGACURE OXE02（BASFジャパン社製）
＊４：チオキサントン系光重合開始剤；KAYACURE DETX-S（日本化薬社製）
＊５：アセトアミノフェノン系重合開始剤；IRGACURE 379（BASFジャパン社製）
＊６：２,２’−チオジグリコール酸（関東化学社製；規格 鹿１級）
＊７：Ｍ−３５０（東亞合成社製）
＊８：カルビトールアセテート
＊９：ＢＹＫ−３５４（ビックケミー・ジャパン社製）
＊１０：不揮発成分を基準として算出。

[Remarks]
* 1: Lightness L * = 70, average particle size = 2 μm
* 2: Lightness L * = 58, average particle size = 1.5 μm
* 3: Oxime ester photoinitiator; IRGACURE OXE02 (BASF Japan)
* 4: Thioxanthone photopolymerization initiator; KAYACURE DETX-S (Nippon Kayaku Co., Ltd.)
* 5: Acetaminophenone polymerization initiator; IRGACURE 379 (BASF Japan)
* 6: 2,2′-thiodiglycolic acid (manufactured by Kanto Chemical Co., Inc .; standard deer grade 1)
* 7: M-350 (Toagosei Co., Ltd.)
* 8: Carbitol acetate * 9: BYK-354 (by Big Chemie Japan)
* 10: Calculated based on nonvolatile components.

<Creation of evaluation circuit>
Each photosensitive conductive paste was applied on the entire surface of the glass substrate using a 200 mesh polyester screen so that the wet film thickness was 14 μm, and dried at 100 ° C. for 20 minutes in an IR drying furnace. A dry coating was formed. In addition, the film thickness of the coating film after drying was 10 μm.

  Next, an ultrahigh pressure mercury lamp was used as a light source for the obtained dried coating film, and a straight line pattern negative mask having a remaining resolution of 10 = 20/90 to 100/100 μm was used through a negative mask. For the blanking resolution, a negative / positive reverse pattern of the negative resolution of the remaining resolution was used. After each pattern exposure, development was performed using a 0.4% sodium carbonate aqueous solution with a liquid temperature of 30 ° C. for a development time of 10 and 20 seconds, followed by washing with water.

(Circuit formability evaluation)
Remaining resolution: negative mask design value of the minimum remaining pattern.
Extraction resolution: Negative mask design value of the smallest space that can be patterned.
The measurement results are shown in Table 2.

(Specific resistance evaluation)
A rectangular pattern having a negative design of 0.4 × 10 (cm) was formed, and the specific resistance value was calculated from the resistance value and the film thickness after thermosetting. The measurement results are shown in Table 2.

As shown in Table 2, it can be seen that both Examples 1 and 2 using the photosensitive conductive paste of the present embodiment have good resolution and removal resolution regardless of silver powder, and have low resistance. Further, it can be seen from the results of Examples 1 and 2 that the patterning is good in the photosensitive conductive paste of this embodiment regardless of the lightness L * value of the conductive powder.
On the other hand, in Comparative Example 1 in which no oxime ester was used as the photopolymerization initiator, photocuring was insufficient and the resolution was lowered. Moreover, since the photocuring of the coating film surface was insufficient, the development resistance was damaged, and the specific resistance value was confirmed to deteriorate. Moreover, it turns out that resistance value deteriorates in the comparative example 2 which did not use at least any 1 type of the derivative of thiodiglycolic acid and thiodiglycolic acid.

Claims (3)

  It contains an organic binder, a conductive powder, a photopolymerizable monomer, an oxime ester photopolymerization initiator, and at least one of thiodiglycolic acid and a derivative of thiodiglycolic acid. Photosensitive conductive paste.   The photosensitive conductive paste according to claim 1, wherein the conductive powder contains silver powder.   A conductive circuit formed using the photosensitive conductive paste according to claim 1.